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Full text of "Alaskan glacier studies of the National Geographic Society in the Yakutat Bay, Prince William Sound and lower Copper River regions"

66                                  ALASKAN GLACIER STUDIES
piedmont bulb where they emerged from their valleys; but between the two was an area that was less raised and broken, being between two different currents of recently accelerated ice motion.
Below Terrace Point the crevassing diminished in amount and finally died out completely before the alder-covered portion of the ablation moraine was reached. This outer portion, beyond the area of crevassing, was apparently in no notable respect different from its 1906 condition. Indeed three lakes showing in the forest in the 1906 photographs were still present on the glacier. There was no crescentic crevassing, such as was so prominently developed in Atrevida Glacier during its advance, and no noticeable thickening of the piedmont portion. This section was still a field of ablation moraine, with the outer fringe of forest and alder grading into a wast;e of barren, undulating, rocky moraine with no ice appearing when viewed from a distance. But in 1909 this desert of ablation moraine graded into an area of gashes in which ice was revealed in increasing amounts up the glacier.
"While there was no noticeable thickening of the piedmont portion of the glacier, there was thickening along the margins at Terrace Point and Lucia Nunatak, and presumably also between these two points. The thickening and advance was best shown at Lucia Nunatak. Here the ice rode high up on the stoss or northern end. The undulating, moraine-covered stagnant ice that in 1906 rested high up on the northern slope of the nunatak was now replaced by an up-domed area of greatly crevassed ice which had overridden the barren area and advanced into the zone of vegetation that covers the nunatak top. At this point, therefore, the glacier was over 100 feet higher than in 1905 and 1906. A peculiar dome of broken ice also rose against the middle of the eastern side of the nunatak, but the cause for this could not be determined at the distance from which we viewed it. The stagnant tongue of Lucia Glacier which formerly stretched down the valley between the nunatak and Floral Hills, and which in 1905 and 1906 was not visible from the crest of Amphitheatre Knob, had been pushed forward and broken into impassable condition so that it was now plainly visible from that viewpoint, and the ice tongue extended a quarter of a mile beyond the southern end of the nunatak. Its total advance is estimated to have been between half and three-fourths of a mile. Whether it united with the main glacier below the nunatak could not be determined, but if it did not actually unite it certainly almost did so, and the hill was once more nearly if not quite a true nunatak.
At Terrace Point the ice had been pushed up laterally and, as already stated, had been greatly broken. During the earlier visits, in 1905 and 1906, this margin was a moderately-sloping, moraine-covered embankment with almost no ice showing, and one could ascend the slope at any point. Now the broken ice was bordered by a jagged precipice from which both moraine and ice blocks were constantly falling. The marginal valley between the glacier and Terrace Point had been greatly narrowed, the ice having pushed out laterally one or two hundred yards. At no point was the ice in contact with Terrace Point and a narrow marginal valley still existed. In the lower portion of this valley stood a narrow linear lake at least a half mile in length and two or three hundred yards wide, with the jagged ice precipice forming one margin and the southern end of Terrace Point the other. This lake was filled with icebergs, and as we looked down upon it we saw many fall into it. At the southern tip of Terrace Point in 1906 a small lake stood where the advancing Atrevida Glacier had pushed forward to dam the drainage from